On the night I get the call about my oldest brother's death, I roll my wisdom teeth in my palm, listening to the click of crown against crown. I prick my pointer finger with the tip of a tangled root, wondering if a dead tooth exposed to the air for eight years is too brittle to pierce skin. I press one of the crowns into my palm until it leaves a bite mark. Years ago, when the dentist finally rooted this tooth out of my jaw after a three-hour extraction, she played with it like a toy.
"It looks like an elephant," she said. "Look at the curly roots! One of them is a trunk."
I laughed as she "walked" it across the back of my hand.
"These are very special and different teeth," she said. "Very rare. I have never seen such roots before. Beautiful."
I turn the teeth over and over, click, click, click like plastic poker chips, and suddenly, I feel compelled to roll them across the floor like dice, to place a bet: my brother had tangled, strange roots like mine. I imagine his teeth as tiny elephants, a dentist playing with them following a long, painful extraction.
Maybe our roots could identify us as siblings.

*

*

A few milligrams drilled from a tooth are all I need to mine oxygen isotopes from my brother's bone and compare them to mine. The isotopes got into his teeth from drinking water, and into the drinking water from rain, and from there, the body transubstantiated them into bone.
Not all raindrops are created equal: Some of their oxygen molecules contain more neutrons, some fewer, lending different atomic weights, either Oxygen-16 or Oxygen-18. The further inland, the less Oxygen-18 in the rain; as clouds float over the land, heavier atoms fall first. Landlocked rain, therefore, is lighter, and so are the teeth built of it, which I like to blame for my molars being so brittle, so easy to crack and break that dentists often insist on caps made of gold.
Scientists can drill a cavity into a molar, extract tooth dust, and pin it to a region on an isotope ratio map, but only roughly. After all, some regions cover a broad swath, and some share identical isotope ratios. As a result, even if my brother's isotopes match mine, it does not mean we were close. It just means the possibility that these two sets of teeth share a common geography, that these bodies shared roots, cannot be ruled out.
Teeth, however, stop forming and changing at a young age, and so the recording clicks off: end of story. For Greg, that means Hawaii, on the naval base where he was born: an island. For me, it means Iowa, where I spent my entire childhood. His isotopes were heavy; mine are light. It feels like a progression: more has been lost each successive generation.
If I want to find out about the recent past, I have to cut to his bones, like archaeology in reverse, the deepest layers the newest. Bones complete the story the teeth started because the body replaces old bone with new bone until late in life, meaning scientists can mine marrow for isotopes revealing whereabouts for the past decade or two. The only exception: the elderly, whose bones rebuild at slower rates; for them, scientists can only uncover clues to a slightly more distant past. The present is lost on them.
Greg, just 51 when he died, was still young enough. If I could exhume him and steal a sample from his femur, I could map the regions he lived in the past decade, like a background check in bone. I could weigh the isotopes: teeth to bones, cradle to grave.
But the truth is: I already know what this background check will find: He ended where I began: in Iowa, just outside Cedar Rapids. His bones and my teeth make a complete set.

*

When my sister called me long distance to tell me our oldest brother died, the news was already one day old. This is always the way with my family, guarding even the most public information—the same fact anyone could glean from a death notice in the local paper—as if it were Cold War intelligence.
"Suicide," I blurted. It had to be suicide. He was only 51 years old, and as far as I knew, in good health. Of course, he could have been hooked up to a respirator or feeding tube for all I knew; nobody would have told me.
"Tell me he committed suicide," I repeated. At least if he shot himself in the head or overdosed on sleeping pills, it would be something—a message, maybe.
My sister ignored this. "Heart attack. But the autopsy is tomorrow. And they're going to test for drugs."
She told me he took prescriptions for back pain. One of our brothers visited him the day before he died, and his skin looked gray. "Is it wrong that I don't care?" She asked.
"No," I said.
But the truth was, I did think it was wrong.
I had not seen my brother for eighteen years—as many years as he was older than me—and even then it was just a glimpse of his red hair in a grocery store parking lot. He saw me, too, and I felt his glare as I walked past. Looking back would have been tantamount to betrayal. Looking back might have meant losing my sister. I wanted to ask if he blamed me, too. I wanted to tell him I missed him, even in spite of everything. I wanted to ask him why.
Prior to that, I had not seen him for six or seven years, not since he was exiled from our lives for good.
My sister and I stayed on the phone line saying nothing, just breathing. Taking it in. We often have conversations like this, without words.
Suddenly, I flashed to an image of my brother's feet, his work boots still pulled on, sticking out from under the blankets of the sofa bed in our living room. I was seven or eight, and my brother was staying with us. I used to sneak down the hall in the middle of the night and peer around the corner to watch him sleep. He never caught me. Which meant he never knew.

*

I search the Internet for my brother's obituary and read it over and over, shielding his photo with my palm. I learn that he raised goats, took walks with his "special nieces," and loved his dog. He graduated from Fort Benning Jump School with honors. He was 51. He still lived in Iowa. He married a woman with the same first name as my mother, which means his wife has my mother's full name—the name mine is meant to be a version of.
But nobody else who reads this obituary will learn that he had a sister—a half-sister, everyone will correct me—named Karrie. I am left off the list.
Teeth and bones: the beginning and the end. All those years in between: nothing.

*

If I could, I would toss my wisdom tooth into his grave. Maybe our bones would be confused. That would be something.

*

Lately, I have a recurring dream of the night Greg lifted me from my bed and carried to me to a bathtub filled with ice cubes and cold water. I was delirious with fever, in and out like a distant radio signal. My brother had come to live with us while between jobs, and so my mother put him to work when the doctor gave the order for the ice bath.
I remember him unbuttoning my pajamas and pulling them over my head. Despite the fever, I giggled at the static electricity from the flannel brushing against my scalp and hair—embarrassed about how I looked to him naked. I hardly knew this man—my brother, so everyone told me—and the truth is, I would have tacked a poster of him up on my wall, right next to the ones from Bop! Magazine, if I could have. I did tack up a Polaroid of him once, but I thought he might laugh at me, and I hid it in a drawer instead. Ever since he arrived at our front door, I found myself going out of my way to harass and tease him. To me, he seemed like a miracle, arriving at just the right time, when I longed for a big brother, someone who could appreciate my bicycle wheelies or the bug cemetery I dug under a bush on the front lawn.
It could not have been too long—maybe three years—after this night that he invited my sister and me, one at a time, for sleepovers at his apartment while his wife worked the graveyard shift, and after that, he was banished from our lives for good. Or maybe it all happened that same year. I get the timeline confused.
My feelings change depending on whether the ice bath flashes into my mind during the daytime or creeps up on me in sleep: In the daytime, this bathtub scene takes on a sweet quality, a moment when I felt like I had a real brother, someone who took care of me in a vulnerable moment. At night, I wake myself up trying to wriggle out from under his legs, shoving his fingers out of my buttonholes.

*

In my favorite photograph of my brother, he wears a ski mask pulled down backwards so the eyeholes sit on the back of his head. He cannot see out the eyeholes, and I cannot see into his eyes:

*

The youngest of my brothers committed suicide within hours of meeting me for the first time. I was eight years old, playing Pac-Man in the arcade room of the underground bowling alley in the Town & Country Shopping Center while my mother knocked down pins with her swirly blue ball and sucked Dr. Pepper through a straw. In those days, she looked like Cher with her long, straight brown hair.
I glanced up from my video game and caught Dad buying soda from a vending machine, leaning on the machine with one hand and gripping the cup with the other, peeking back at Mom like a kid trying to get away with something. He carried the plastic cup to a corner table, where a teenage boy sat waiting, his chin resting on his hands. My cheeks burned. Dad never bought me sweets, especially soda (cocaine-water in a can, he called it). I walked up to introduce myself, but my father spoke first.
"This is Jimmy," he said, wrapping one arm around the boy's shoulders and squeezing.
The boy flinched and sank in his chair to escape the hook of my father's arm. He reached out his hand, and I shook it. I did not know he was my brother, not until I saw his picture in the newspaper obituaries and my father said, "That's your brother, Jimmy." Jimmy. My brother. Self-inflicted gunshot wound to the chest.
It was not until years later I learned my father adopted him with a previous wife, but the adoption was rescinded before I was born.
Looking back, I search my memory for a sign. He must have had it all planned out: the loaded gun, hidden beneath his mattress or pillow, maybe folded inside a sweater, pushed to the back of a drawer. I imagine him pulling the trigger, a cold metal barrel against his heart, and this much I know: I held the same hand that killed him, just not long enough.

*

My second oldest brother—a half-brother, too—is missing a finger.
I never noticed until he and I sat side-by-side in my parent's living room for the first and last time in our lives. He uncrossed his arms to stretch, and I saw the stub.
An accident, he told me, when he caught me staring at the scar tissue. "Before you were born."
I wondered how many secret fractures I would never see, how many bone fragments chipped away before I was born.

*

I email a friend links to both versions of my brother's obituary: the first one and the correction published just one day later. Whoever called in the correction misspelled my name. Carrie with a C.

"I could never understand what 'half brother' really means," I write in my email to the friend. No matter what term I use, I am a liar: My brother is not my brother. My brother is my brother. I feel the same way about the obituaries. Neither one tells the complete truth. I have to read them both together, one without me and one with. Sometimes I wonder if anyone noticed the correction and caught on to its implications. So many historians and genealogists mine obits for nuggets of history, but really, most of them are lies.
"You and your brother look alike," my friend writes back. "Especially around the eyes."
Her email is better than a DNA test, and more meaningful, precisely because she does not require a cheek swab or blood draw. And she does not say, "half." Instead, my friend squinted into my brother's mug shot and made the identification just by looking.

*

In case Lucretius was right—that the outermost layers of things peel away and flit through the air—I take a knife tip to a photograph of my brother, extract a tooth, and eat it.

*

Hiding on the inside of a gun barrel are two kinds of markings that make it unique: first, drill marks left behind when a solid steel bar is hollowed to make the barrel; and second, spiral rifling grooves—otherwise known as the "twist"—cut or impressed into the inside surface. Twist puts a spin on the bullets, the same way a basketball player at the free-throw line puts a spin on the ball. Without twist, bullets would shoot out the business end of the pistol and immediately fizzle, tumbling off course, somersaulting end over end, rendering them less accurate and therefore less lethal.
As a bullet spins through the barrel, the grooves and drill marks cut into its surface, etching a self portrait of the gun's most intimate parts, leaving an individual fingerprint, a bite mark, a sample of the barrel's DNA. Ballistics experts call these "tool marks," and in the forensics lab, they can compare two bullets under a microscope to match them up: these two bullets are siblings, fired from the same pistol, scarred in exactly the same way.

*

All the day of my brother's autopsy, I flash to images of his hands falling down from the sides of the autopsy table. I imagine his cuticles as blue as the gunpowder burns under my fingernails when a cap gun misfired. I still had those burns, little bluish gray dots, like tattooed targets, the day my brother let me fire his Beretta. We were out at a quarry or ravine. My father—our father—was teasing me about how the kick in his rifle knocked me on my ass.
"Try this instead," my brother said, and he kneeled down beside me, curled my fingers around the grip of his pistol, and lifted my arms up to point it safely away. "Funny. Those targets on your fingers are pointing instead of being pointed at." He cupped his hands under mine to steady my aim and counted to three.

*

I scrape my wisdom tooth against the blade of a pencil sharpener and wonder whether the shavings, if consumed, would throw off the isotopes in my bones. How many grams of tooth—my own tooth—would I have to swallow in order to forge a phony geographic record in my patella or femur?

*

"Why did he choose me?" My sister's voice echoes in her bathroom as she asks her usual question about our brother. She never got an answer because he denied all the way to the grave anything happened.
I hear the squeak of her legs against the bathtub and flashback to the ice bath again. The ice cubes clink as my buttocks submerge in the water. I am too weak to resist the cold, and in truth, it feels good. Was that really my brother who slid me into the ice water?
"What if he didn't?" I ask.
In all the chaos after my sister told about her sleepover with Greg, nobody ever asked what, if anything, happened to me. Not that I had a specific memory back then: only blurry, vague images of him letting me win at wrestling matches and thrusting his pelvis under my crotch as I straddled him in victory, or his coarse 5 o'clock shadow scratching my chin as he slipped his tongue over mine. The bloody pulp I discovered in my underwear when I was seven or eight (or was I ten?): not just a bloodstain but pulp. My mother took me to what she called a "woman doctor," but nothing came of it.
It was not until the mid-1990s, when I came home on a visit from college and my father, drunk, picked a fight that I screamed it out for the first time, he did it to me, too. And I never spoke of it to him again.
I know I will regret it almost immediately, but I ask my sister, anyway: "What if it happened to me, too?"
My sister repeats her original question: "Why me?"

*

Newer forensics techniques exploit heat and humidity to reveal human fingerprints on bullets, developing them slowly, like Polaroid prints on the surface of the metal. As a result, prosecutors can trace bullets all the way back to the precise moment they were loaded into the clip. A bullet transforms into a little black box, recording its journey from hand to barrel to heart.
But there is one problem: The match relies partly—maybe even mostly—on judgment. For both fingerprints and bullets, no set standards exist for the number of similarities that must exist before two can be said to come from the same source. Ballistics experts match up partial striations under the lens of a comparative microscope; fingerprint examiners compare swirls and whorls, adding up the number of matching lines. Mistakes happen. It is not like DNA: unimpeachable, perfect.

*

DNA, just DNA, all by itself, can damage you. Even just getting it on your skin can alter your code, permanently, like a virus you cannot treat. When my brother smeared his saliva on my tongue and lips, for just that moment, our half-DNA became whole. The very violation of boundaries created the brother-sister bond we never had.
Sometimes, I wish the damage were obvious, visible, like a sunburn. I imagine my brother's saliva as thymidine dinucleotide, a fragment of DNA that reacts with human skin like concentrated sunlight: When it hits the skin, it tans it, mimicking melanogenesis. The artificial tan stimulates DNA repair, too. Imaginary damage at the surface protects you from real damage down deep. The damage is the cure.
I wish there were some way to extract the snippets of DNA my brother and I shared, to slather them on my skin or inside my lips or eyelids or ears, to turn my whole body into a petri dish and monitor the reaction, as cool and objective as a scientist.
Am I so desperate for a brother that I am willing to exaggerate a partial match?

*

"Those are some funky, twisted roots," the dentist says, leaning back in his chair as he examines the x-rays of my back molars, deciding on a treatment plan for Tooth 19, the molar that recently turned so electric I stopped eating all raw vegetables and fruits, all berries with seeds, cold food, hot food, chewy food, acidic food, sweet food, and crunchy food. I have been channeling small bites of soft, room-temperature chicken to the right side of my mouth, carefully chewing and swallowing to keep morsels from straying to the exposed nerve lying in wait. If even the tiniest particle makes contact, I pay the price by writhing on the floor for minutes at a time, moaning while I press my hand into my cheek. Water has to warm up to room temperature; coffee has to cool down.
I feel the dentist watching me as I examine the x-ray images, my eyes following the lines of the tangled roots, searching for the end. They have to stop somewhere, I think. They do not look like bone to me. They look like sea anemones:

"These are the kind of roots I expect to see with significant trauma," he says. "Like an assault with a baseball bat. You ever have a trauma there?" He points at Tooth 19. "Ever get hit or fall down or anything like that?"
Something about the way he asks the question takes me back to when I was thirteen and the Department of Human Services sent an interviewer to my house to follow up on a black eye. I cannot put my finger on it, but a certain tone transmits just under the audible register for most people, but well within hearing range of someone who grew up tiptoeing over booby-trapped eggshells. Even when I let myself forget about the IBEW belt buckle about to slam down on my bones or my father lifting my skirt to comment on how much the boys must like it or my grown brother sticking his tongue through my teeth, I cannot let go of this sixth sense for when conversations turn forensic. I already know this dentist is a forensic dentist because I investigated his background. He is interviewing me like one of his pediatric patients with suspicious injuries or malnourished teeth.
I see the way he glances at my hands, clenched into fists and pressed hard together between my thighs like a lock, a reflex of mine. I see him glance at my forearm, the one with all the linear scars running horizontally across. The cuts there healed ghostly white just like root canals on an x-ray. These days, I do not always cover them. I see him notice, and I think he sees me noticing him. He asks again about potential trauma, and I mention my seizures one more time.
Of the past five dentists I have seen, at least four of them have immediately recognized my epilepsy without my disclosing it. They could tell by the patterns of damage.
He looks back to the radiographs. I glare at him as he stares at my tooth roots, exposed by his omniscient machines. These x-rays, however, refuse to tell the whole story. Are the seizures a proxy for something else? He comes round full circle to his original theory: someone bashed me upside the jaw with a blunt object.
Or a fist.
Or I fell.
He turns toward me, and I quickly look away and look back.
"No falls or anything like that?" He asks. "You sure?"

*

Greg died a fugitive from justice. He was never on the lam. There was no car chase. No shootout. No wanted poster. He turned himself into a fugitive by dying—escaping, Houdini-like, just a few days before facing trial for Sexual Abuse in the 2nd degree, a Class B Felony in the state of Iowa, carrying a penalty of up to 25 years in prison. Three days after he died, the court entered a disposition:

But I do not know any of this until five years later, not until I run a background check and piece together his last days:
On Wednesday, September 24th, 2008, Greg's attorney told him: Take a plea. Prosecutors have too much.
He meant the phone call, the one police set up to coax a recorded confession. We were just wrestling, Greg said in the taped call to his accuser, a relative who was under twelve at the time he "wrestled" her. You misunderstood. I need you to tell the truth, the accuser urged, about our secret.
Greg must have possessed a tacit understanding: the only way to lock up the secret forever was to spring open the cell. This is how the game works: reaffirm the covenant.
The victim turns the key for you.

...

...

...

I recognize that threat, not from him but from family ever since: I am the family destroyer, not him. This is how the game works: The victim lets the skeletons out of the closet, and she is to blame.
Three days later, a judge approved the warrant for his arrest, and he spent his last Christmas on Earth in jail awaiting arraignment and $25,000 bail.
Two days after his attorney told him to take the plea and three days before trial, he was dead.
A heart attack, I was told: both the truth and a lie.
Years later, I learn the coroner mailed a sample of Greg's blood to a forensics lab out of state, where toxicology tests determined prescription drugs may have killed him but could not make the call on accident or suicide. At least if it was suicide, it would mean something.
It does mean something: he took the plea.

*

All this time, I imagined Greg buried in a cemetery in Iowa, but now I know he was cremated, reduced to a fine dust, which I imagine the texture of gunpowder. Teeth and bones, beginning and end, jumbled.
We are no longer a complete set.
If I could, I would steal the urn. I would wet the ashes with Iowa rainwater and grind them in a mortar and pestle with gum Arabic to make fine bone black ink, the way the ancients made their inks. I would dip a pen in his remains and forge his plea, signing it in his own hand.
On his plea of not guilty in the court file, he signed his name, and it is the first time I have ever seen his signature:

When I copy it, practicing over and over in my own hand, I realize: he wrote his last name like me. Half our names look just alike, and it is the half of the parent we have in common. Maybe this, our handwriting, can identify us as siblings.

I would forge his full confession: I kissed my seven-year-old sister with my tongue, and I knew it was wrong. I made her bleed between her legs, and I knew it was wrong.
Who could ever detect such a forgery, signed as it is with his DNA?
Then, I would mix the remaining ashes into a paste and apply it like a poultice to comfort me for the loss of my specialness, my sisterness. He did not touch me to make me his sister, to mingle our DNA into a unambiguous whole; he touched me because it was who he was. He was, as far as I can tell from his shaky signature on the plea, nervous because he was finally exposed: a common pedophile, nothing more.
What he denies me, I can give myself: If I steal that urn, I can dip my fingertip in him and polish my eyeteeth: damage at the surface to prevent damage down deep; beginning and end; bones to teeth. Half-sister becomes sister.

*

I have no legal right to do what I am doing. I am not immediate next-of-kin under Iowa law, only kin—and half-kin at that. I request the autopsy report, anyway, betting all hopes on my name: Karrie, so similar to my mother's name, whose name is exactly his widow's. Daughter becomes mother becomes sister-in-law. I write Karrie on the line and wonder what Greg would think of me picking the lock to his secrets on that basis: sister becomes wife.
I will never know if my name was the key, but the medical examiner releases the report and mails it an envelope stamped "confidential."
By the time his body was discovered, rigor mortis had set in. He was naked, resting on his knees and arms, face pressed into the floor, as if he had slumped out of his love seat while watching television. Drugs in his system: morphine, methadone, gabapentin, diazepam, desmethyldiazepam. His mouth had putrefactive decay, so much the coroner could not examine his teeth. On the one hand, I am disappointed. On the other, I am glad for it. The teeth are mine, I think. Our secret.
At the end of the report, there it is in black and white, the final, Rorschach diagnosis:

Like an ink-blot test, whatever you see in that final diagnosis reveals more about you than him: If you believe the tape recording, he overdosed on pills to escape justice. If you believe he was innocent, he suffered a heart attack. If you believe he was guilty but felt remorse, maybe either theory is true.
It takes two days re-reading the report to finally see it: His autopsy was performed in the morgue of the same hospital where I was born. His body ended where mine began. A complete set.

*

I lose my elephant tooth for good when I attempt to make it into art. I suspend it in wax inside the clear plastic dome of a pencil sharpener—the kind that comes in a cheap school supplies kit. I drop in the tooth, snap on the sharpener bottom, and wait for the wax to dry. I want to see my tooth suspended in there, hovering above the blades. But the wax dries too opaque, too bone-like, and I can barely make out the tip of one curly root, still stained a little pink.
I cannot stand to look at that pink root, and extracting it from the wax is too much to bear. I drop it in the kitchen waste can and haul the bag to the apartment trash before I can change my mind. Goodbye, twisted roots, I think, as I shove the plastic bag down the throat of the chute.
Then I realize how perfect it is like that, lost to the landfill, how the plastic sharpener will never decay, and my tooth will be preserved for eternity, suspended above the blade, its pink, twisted elephant trunk like a quill almost touching the penknife.

*

When I file a Freedom of Information Act request for the police recording of my brother's confession, I know my request will be denied, and that is exactly what I want: to force the system to tell me no—to deny me. That, at least, will be something: a kind of justice, the only justice I know. Mostly, though, I want to force my name into the case record, next to my brother's mug shot, shuffled in with his confession: my plea; his confession: Maybe our words will be confused. That would be something.
And I am right: The police never send me the recording. Instead, they mail me a 40-page file with names and addresses redacted the old-fashioned way: blacked out with a Sharpie. I already know the names. I already know the addresses. I even Google map them sometimes, zooming in on houses, tapping into public secrets. What I do not know is how my brother spent his last free day before the phone call transformed him into a sex abuse suspect:

My tongue licks the root canal on Tooth 19 as I read it, as if the nerve were still raw. Teeth and bones.
And now, the last surviving photograph of my brother is this: a Kenny Rogers lookalike standing before a backdrop of fake wood paneling, his hair and skin rapid-aged far beyond his fifty-one years, no tension in his face, only resignation, standard-issue jail stripes with the faint hint of XL written in Sharpie leaking through above where a chest pocket normally would be. His eyes are in shadows, and when I lighten the photo, I still cannot see them well, except that one appears to wander to his left, my right, focusing on something outside the frame. It does not feel as honest as the backward ski mask:

He holds no placard. I really wanted it. I wanted to see him holding the booking number. There is my denial, the no I equate with justice.
His lips are sealed. No teeth.

*

Greeting card aisle: sympathy for loss of child, loss of parent, loss of uncle, loss of aunt, loss of grandparent—no card for loss of sibling.
I wrap a wisdom tooth in my brother's obituary and slide it into the slot for birthday: brother.

The baby-tooth of this piece was a flash nonfiction essay that earned me an interrogation about whether it was true, which set off a forensics investigation, which caused me to lose faith in forensics, until a forensic dentist refused to accept my explanation for those twisted roots.